Refrigerant compressor and refrigeration appliance using same

ABSTRACT

A synthetic resin film is formed on a region of a valve plate ( 117 ) which is brought into contact with an arm portion of a suction valve ( 120 ) or a region of the valve plate ( 117 ) which is brought into contact with an arm portion of a discharge valve ( 121 ). With such a configuration, delay in opening of the suction valve ( 120 ) or the discharge valve ( 121 ) caused by adhesion force of refrigerating oil is suppressed so that a pressure loss in a suction stroke or a discharge stroke can be reduced whereby compressor efficiency is enhanced. Further, a striking sound generated at the time of closing the suction valve ( 120 ) or the discharge valve ( 121 ) is reduced by an elastic effect of the synthetic resin film so that the reduction of noises is realized.

TECHNICAL FIELD

The present invention relates to enhancement of efficiency and reductionof noises of a refrigerant compressor used mainly in a household-userefrigerator.

BACKGROUND ART

In keeping with a trend of energy saving of household-use refrigerator,along with the progress of a variable-speed operation using an inverteror a sensor control and the expansion of the scope of the variable-speedoperation, there has been a demand for steady increase of efficiency ofa refrigerant compressor.

As a conventional refrigerant compressor, there has been known arefrigerant compressor where a valve plate is disposed on an opening endof a cylinder, has a suction valve seat disposed so as to surround asuction hole and a discharge valve seat disposed so as to surround adischarge hole, and is formed by molding using a sintered metal material(see Patent Literature (PTL) 1, for example).

FIG. 22 is a cross-sectional view of the conventional refrigerantcompressor described in PTL 1, and FIG. 23 is an exploded perspectiveview of the valve plate and parts around the valve plate of theconventional refrigerant compressor.

As shown in FIG. 22 and FIG. 23, in the refrigerant compressor,refrigeration oil 2 is accumulated on a bottom portion of the inside ofsealed container 1, sealed container 1 is filled with working fluid 3,and compressor body 4 is housed in sealed container 1.Electrically-operated element 6 and compressive element 9 areresiliently supported by suspension spring 5 in sealed container 1.

Electrically-operated element 6 includes stator 7 and rotor 8.

Compressive element 9 includes: crankshaft 12 provided with eccentricshaft 10 and main shaft 11, cylinder 14 in which compressor chamber 13is formed, bearing portion 23 which supports main shaft 11; and piston16 which reciprocates in cylinder 14. Compressive element 9 alsoincludes: valve plate 17 which seals an end surface of cylinder 14;suction valve 20 and discharge valve 21 which are mounted on valve plate17 and respectively open and close suction hole 18 and discharge hole 19which allow the inside and the outside of compression chamber 13 tocommunicate with each other; and a connecting portion (not shown) whichconnects eccentric shaft 10 and piston 16 to each other.

On a side of valve plate 17 opposite to compression chamber 13, cylinderhead 52 is disposed so as to cover valve plate 17 as a cover, and headspace 56 is formed by valve plate 17 and cylinder head 52.

Main shaft 11 of crankshaft 12 is rotatably and pivotally supported bybearing portion 23, and is fixed with rotor 8.

Next, the operation of a conventional refrigerant compressor isdescribed.

In the refrigerant compressor, when a magnetic field is generated bysupplying an electric current to stator 7 and rotor 8 fixed to mainshaft 11 is rotated, crankshaft 12 is rotated, and piston 16reciprocates in cylinder 14 by way of a connecting portion (not shown)mounted on eccentric shaft 10 so that a series of cycles including asuction stroke, a compression stroke, and an discharge stroke isrepeated.

In the suction stroke, when piston 16 is operated in a direction that avolume of cylinder 14 is increased, working fluid 3 in compressionchamber 13 expands, and when a pressure in compression chamber 13becomes lower than a pressure on a low pressure side of a refrigerationcycle (not shown), suction valve 20 is started to open. Then, workingfluid 3 of a low temperature which returns from the refrigeration cycleflows into compression chamber 13 through suction hole 18. At this stageof operation, discharge valve 21 closes discharge hole 19 formed invalve plate 17.

Then, in the compression stroke, when piston 16 turns the direction ofmovement to the direction that the volume of compression chamber 13 isdecreased from the position of bottom dead center where the volume ofcompression chamber 13 becomes largest, the pressure in compressionchamber 13 is elevated, and due to the pressure difference between thepressure in compression chamber 13 and the pressure of the refrigerationcycle lower-pressure side (not shown), suction valve 20 is closed sothat compression chamber 13 is closed.

Thereafter, when piston 16 is further operated in the direction that thevolume of compression chamber 13 is decreased, working fluid 3 iscompressed and the pressure in compression chamber 13 is elevated to apredetermined pressure.

In the discharge stroke, when pressure of working fluid 3 in compressionchamber 13 is elevated and becomes higher than a pressure in head space56 formed by valve plate 17 and cylinder head 52, discharge valve 21 isstarted to open due to the pressure difference. Then, working fluid 3 incompression chamber 13 passes through discharge hole 19 and flows out tohead space 56. Thereafter, working fluid 3 is discharged to a highpressure side (not shown) of the refrigeration cycle from head space 56through a discharge muffler (not shown).

In general, recessed portions are formed on valve plate 17 so as toarrange suction hole 18, discharge hole 19, and discharge valve 21 andhence, valve plate 17 has a complicated shape whereby valve plate 17 ismade of a sintered metal material for enhancing productivity.

However, in the conventional configuration, valve plate 17 is made of asintered metal material and hence, open pores peculiar to a sinteredmetal material are present in the sintered metal material in a scatteredmanner. Accordingly, when refrigeration oil 2 in the compressor pools ona surface of valve plate 17 and impregnates into the inside of valveplate 17. Impregnated refrigeration oil 2 exudes to the surface of valveplate 17 due to a change in pressure or the like. Such refrigeration oil2 is interposed in a gap formed between valve plate 17 and suction valve20 and discharge valve 21. Accordingly, a valve opening operation isobstructed by an adhesion force of refrigeration oil 2 interposedbetween contact surfaces of valve plate 17 and the respective valves andhence, resistance which a passing working fluid receives is increasedand a pressure loss is generated thus giving rise to a drawback thatefficiency of the compressor is lowered.

Further, valve plate 17 and suction valve 20 as well as valve plate 17and discharge valve 21 generate a striking sound when the valve isclosed. The striking sound leaks to the outside of the sealed containerthus giving rise to a drawback that noises are generated. Particularly,electrically-operated element 6 adopts inverter driving to satisfy ademand for high efficiency so that electrically-operated element 6 isoperated at a low speed whereby noises which electrically-operatedelement 6 generates are decreased. As a result, a striking soundgenerated between valve plate 17 and suction valve 20 as well as betweenvalve plate 17 and discharge valve 21 become conspicuous thus making anoise problem more serious.

It is an object of the present invention to enhance efficiency of acompressor by suppressing delay in opening of suction valve 20 anddischarge valve 21 thus decreasing a pressure loss in a suction strokeand a discharge stroke. It is another object of the present invention torealize the reduction of noises by lowering a striking sound generatedbetween valve plate 17 and suction valve 20 as well as between valveplate 17 and discharge valve 21 in the valve closing operation.

CITATION LIST Patent Literature

PTL 1: Unexamined Japanese Patent Publication No. 2000-45949

SUMMARY OF THE INVENTION

A refrigerant compressor according to the present invention includes,inside a sealed container: a cylinder which houses a piston movable in areciprocating manner; a valve plate which is disposed on an opening endof the cylinder and has a suction valve seat formed so as to surround asuction hole; and a suction valve configured to open and close thesuction hole. The suction valve includes an opening and closing portion,and an arm portion to be operated along with opening and closing of theopening and closing portion, and the refrigerant compressor furthercomprises a synthetic resin film in at least a region of the valve platewhich is brought into contact with the arm portion of the suction valve.

With such a configuration, it is possible to suppress delay in openingof the suction valve caused by an adhesive force generated byrefrigeration oil interposed in the gap formed between the valve plateand the suction valve. By suppressing delay in opening of the suctionvalve, it is possible to provide a refrigerant compressor which enhancescompressor efficiency and a refrigeration appliance using the same.

Further, a striking force generated between the valve plate and thesuction valve at the time of closing the suction valve can be reduced byan elastic effect of the synthetic resin film applied to the valve plateand hence, a striking sound can be reduced thus realizing the reductionof noises.

A refrigerant compressor according to the present invention includes,inside a sealed container: a cylinder which houses a piston movable in areciprocating manner; a valve plate which is disposed on an opening endof the cylinder and has a discharge valve seat formed so as to surrounda discharge hole; and a discharge valve configured to open and close thedischarge hole. The discharge valve includes an opening and closingportion, and an arm portion to be operated along with opening andclosing of the opening and closing portion, and a synthetic resin filmis applied to at least a region of the valve plate which is brought intocontact with the arm portion of the discharge valve.

With such a configuration, it is possible to suppress delay in openingof the discharge valve caused by an adhesive force generated byrefrigeration oil interposed in the gap formed between the valve plateand the discharge valve. By suppressing delay in opening of thedischarge valve, it is possible to provide a refrigerant compressorwhich enhances compressor efficiency and a refrigeration appliance usingthe same.

Further, a striking force generated between the valve plate and thedischarge valve at the time of closing the discharge valve can bereduced by an elastic effect of the synthetic resin film applied to thevalve plate and hence, a striking sound can be reduced thus realizingthe reduction of noises.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a cross-sectional view of a refrigerant compressor accordingto a first exemplary embodiment of the present invention.

FIG. 2 is an exploded perspective view showing a valve plate of therefrigerant compressor and parts around the valve plate according to thefirst exemplary embodiment of the present invention.

FIG. 3 is a cross-sectional view showing a main part of the refrigerantcompressor according to the first exemplary embodiment of the presentinvention.

FIG. 4 is a plan view of a suction valve of the refrigerant compressoraccording to the first exemplary embodiment of the present invention.

FIG. 5 is a plan view of a discharge valve of the refrigerant compressoraccording to the first exemplary embodiment of the present invention.

FIG. 6 is a plan view of the valve plate on a suction side of therefrigerant compressor according to the first exemplary embodiment ofthe present invention.

FIG. 7 is a cross-sectional view of a synthetic resin film of therefrigerant compressor according to the first exemplary embodiment ofthe present invention.

FIG. 8 is a characteristic view showing a value of collision impactaccompanying with opening and closing of a valve of the refrigerantcompressor according to the first exemplary embodiment of the presentinvention.

FIG. 9 is a cross-sectional view of a main part of a refrigerantcompressor according to a second exemplary embodiment of the presentinvention.

FIG. 10 is a plan view of a valve plate on a discharge side of therefrigerant compressor according to the second exemplary embodiment ofthe present invention.

FIG. 11 is a schematic view showing a configuration of a refrigerationappliance according to a third exemplary embodiment of the presentinvention.

FIG. 12 is a cross-sectional view of a refrigerant compressor accordingto a fourth exemplary embodiment of the present invention.

FIG. 13 is an exploded perspective view of a valve plate of therefrigerant compressor and parts around the valve plate according to thefourth exemplary embodiment of the present invention.

FIG. 14 is a cross-sectional view showing a main part of the valve plateof the refrigerant compressor according to the fourth exemplaryembodiment of the present invention.

FIG. 15 is a plan view of the valve plate of the refrigerant compressoraccording to the fourth exemplary embodiment of the present invention.

FIG. 16 is a cross-sectional view showing a surface treatment film ofthe refrigerant compressor according to the fourth exemplary embodimentof the present invention.

FIG. 17 is a cross-sectional view of a main part of a valve plate of arefrigerant compressor according to a fifth exemplary embodiment of thepresent invention.

FIG. 18 is a plan view of the valve plate of the refrigerant compressoraccording to the fifth exemplary embodiment of the present invention.

FIG. 19 is a cross-sectional view of a main part of a valve plate of arefrigerant compressor according to a sixth exemplary embodiment of thepresent invention.

FIG. 20 is a plan view of the valve plate of the refrigerant compressoraccording to the sixth exemplary embodiment of the present invention.

FIG. 21A is a cross-sectional view of a main part of a valve plate of arefrigerant compressor according to a seventh exemplary embodiment ofthe present invention.

FIG. 21B is a cross-sectional view of the valve plate of the refrigerantcompressor according to the seventh exemplary embodiment of the presentinvention.

FIG. 22 is a cross-sectional view of a conventional refrigerantcompressor.

FIG. 23 is an exploded perspective view showing a valve plate and partsaround the valve plate of the conventional refrigerant compressor.

DESCRIPTION OF EMBODIMENT

Hereinafter, exemplary embodiments of the present invention aredescribed with reference to drawings. The present invention is notlimited by these exemplary embodiments.

First Exemplary Embodiment

FIG. 1 is a cross-sectional view of a refrigerant compressor accordingto a first exemplary embodiment of the present invention. FIG. 2 is anexploded perspective view showing a valve plate of the refrigerantcompressor and parts around the valve plate according to the firstexemplary embodiment of the present invention. FIG. 3 is across-sectional view showing a main part of the refrigerant compressoraccording to the first exemplary embodiment of the present invention.FIG. 4 is a plan view of a suction valve of the refrigerant compressoraccording to the first exemplary embodiment of the present invention.FIG. 5 is a plan view of a discharge valve of the refrigerant compressoraccording to the first exemplary embodiment of the present invention.FIG. 6 is a plan view of the valve plate on a suction side of therefrigerant compressor according to the first exemplary embodiment ofthe present invention. FIG. 7 is a cross-sectional view of a surfacetreatment applied to the refrigerant compressor according to the firstexemplary embodiment of the present invention.

In FIG. 1 to FIG. 6, in the refrigerant compressor according to thefirst exemplary embodiment of the present invention, for example,mineral oil having low viscosity is accumulated on a bottom portion ofsealed container 101 as refrigeration oil 102. For example, R600a or thelike which is a hydrocarbon refrigerant having a low global warmingcoefficient is filled in sealed container 101 as working fluid 103.

Sealed container 101 is formed by drawing a steel plate. Sealedcontainer 101 includes: suction pipe 150 having one end thereofcommunicating with the inside of sealed container 101 and the other endthereof connected to a low pressure side of a refrigeration cycle (notshown); and discharge pipe 157 having one end thereof penetrating sealedcontainer 101 and communicating with a discharge muffler (not shown) andthe other end thereof connected to a high pressure side of therefrigeration cycle (not shown).

In the inside of sealed container 101, compressor body 104 provided withcompressive element 109 and electrically-operated element 106 is housedin a resiliently supported manner with respect to sealed container 101by suspension spring 105.

Compressive element 109 is formed of crankshaft 112, block 115, piston116, connecting portion 122, and the like. Crankshaft 112 includeseccentric shaft 110 and main shaft 111. Crankshaft 112 also includes oilsupply mechanism 151 formed of a spiral groove formed on a surface ofmain shaft 111.

Electrically-operated element 106 is formed of; stator 107 threadedlyfixed to a lower side of block 115 by bolts (not shown), and rotor 108which is disposed coaxially inside stator 107 and is fixed to main shaft111 by shrinkage fitting. Electrically-operated element 106 is driven byan inverter drive circuit at a plurality of operation frequenciesincluding an operation frequency (for example, 25 Hz=1500 r/min) below acommercial power source frequency.

In block 115, cylinder 114 which forms compression chamber 113 thereinand bearing portion 123 which rotatably and pivotally supports mainshaft 111 are integrally formed with each other.

On an end surface of cylinder 114 are mounted valve plate 117 which isis formed by molding using a sintered metal material and has suctionhole 118 and discharge hole 119 which allow the inside and the outsideof compression chamber 113 to communicate with each other; suction valve120 which opens and closes suction hole 118; and cylinder head 152 whichforms a lid for valve plate 117. All of valve plate 117, suction valve120, and cylinder head 152 are pressed and fixed to the end surface ofcylinder 114 by head bolts 153 so as to seal the end surface of cylinder114. Suction muffler 154 is held and fixed between valve plate 117 andcylinder head 152.

Suction valve seat 141 is formed around suction hole 118 of valve plate117 such that suction valve seat 141 surrounds suction hole 118, anddischarge valve seat 142 is formed around discharge hole 119 such thatdischarge valve seat 142 surrounds discharge hole 119.

Suction valve 120 includes opening and closing portion 120 a which opensand closes suction hole 118, and arm portion 120 b to be operated alongwith opening and closing of opening and closing portion 120 a.

Further, on a surface of valve plate 117 disposed on cylinder head 152side, a discharge valve unit is mounted. The discharge valve unit isformed of; spring lead 130 on which discharge valve 121 which opens andcloses discharge hole 119 is disposed and which resiliently supportsdischarge valve 121; and valve stop 131 which fixes discharge valve 121and spring lead 130. Head space 156 is formed by valve plate 117 andcylinder head 152.

Discharge valve 121 includes opening and closing portion 121 a whichopens and closes discharge hole 119, and arm portion 121 b to beoperated along with opening and closing of opening and closing portion121 a.

The operation and function of the refrigerant compressor having theabove-mentioned configuration are described hereinafter.

In the refrigerant compressor, when a magnetic field is generated bysupplying an electric current to stator 107 so that rotor 108 fixed tomain shaft 111 is rotated, crankshaft 112 is rotated, and piston 116reciprocates in cylinder 114 by way of connecting portion 122 rotatablymounted on eccentric shaft 110. Along with the reciprocating movement ofpiston 116, working fluid 103 is sucked into compression chamber 113through suction muffler 154, and after being compressed, working fluid103 is discharged to a refrigeration cycle (not shown) through dischargehole 119 and head space 156.

Next, a suction stroke, a compression stroke, and a discharge stroke ofcompressor body 104 are described.

In the suction stroke, when piston 116 is operated in a direction that avolume of compression chamber 113 is increased, working fluid 103 in theinside of compression chamber 113 is expanded, and a pressure incompression chamber 113 becomes lower than a pressure in suction muffler154, due to the difference between the pressure in compression chamber113 and the pressure in suction muffler 154, suction valve 120 isstarted to open. Then, arm portion 120 b of suction valve 120 isoperated and hence, working fluid 103 of a low temperature which hasreturned from the refrigeration cycle (not shown) is temporarilyreleased into sealed container 101 from suction pipe 150 and,thereafter, flows into compression chamber 113 through suction muffler154.

Thereafter, in the compression stroke, when piston 116 turns thedirection of movement to the direction that the capacity of compressionchamber 113 is decreased from the bottom dead center, the pressure incompression chamber 113 is elevated, and due to the difference betweenthe pressure in compression chamber 113 and the pressure in suctionmuffler 154, suction valve 120 is closed. Then, compression chamber 113is closed, and piston 116 is operated in the direction that the volumeof compression chamber 113 is decreased and hence, working fluid 103 iscompressed, and the pressure in compression chamber 113 is elevated to apredetermined pressure.

Then, in the discharge stroke, when the pressure of working fluid 103 incompression chamber 113 is elevated and becomes higher than a pressurein head space 156 formed by valve plate 117 and cylinder head 152. Whena force generated by the pressure difference exceeds a force forresiliently deforming discharge valve 121, discharge hole 119 is opened.Then, arm portion 121 b of discharge valve 121 is operated and hence,working fluid 103 in compression chamber 113 passes through dischargehole 119 and flows out into head space 156.

Thereafter, working fluid 103 passes through a discharge muffler (notshown) from head space 156, and is discharged to a high-pressure side ofthe refrigeration cycle (not shown) through discharge pipe 157.

When the pressure difference between head space 156 and compressionchamber 113 is decreased, a force which is generated by the pressuredifference and is applied to discharge valve 121 becomes smaller than arestoring force of spring lead 130 and discharge valve 121, dischargevalve 121 is closed so that compression chamber 113 is closed. As aresult, piston 116 moves in a direction toward the bottom dead center,and the refrigerant compressor is shifted to the suction stroke again.

In the refrigerant compressor of this exemplary embodiment, syntheticresin film 160 is formed on at least a region of valve plate 117 whichis brought into contact with arm portion 121 b of suction valve 120.

Synthetic resin film 160 contains a synthetic resin made of fluororubberas binder 161, and contains a fluororesin as solid lubricant 162 in anapproximately-uniformly scattered manner.

Synthetic resin film 160 having the above-mentioned structure is formedby a following method.

Firstly, a temperature of valve plate 117 is elevated to a predeterminedtemperature by applying preheating to valve plate 117. The preheating isperformed for evaporating a solvent dissolved in synthetic resin film160 which is applied by coating to the region of valve plate 117 whichis brought into contact with arm portion 120 b of suction valve 120 thusapplying synthetic resin film 160 to valve plate 117 uniformly.

A surface treatment agent which contains solid lubricant 162 and whosecomposition is adjusted is applied by spraying to the region of valveplate 117 which is brought into contact with arm portion 120 b ofsuction valve 120. In applying the surface treatment agent, a maskingjig having a shape suitable for preventing adhesion of a coating agentto an undesired place is mounted on valve plate 117.

Thereafter, preliminary drying is performed for several minutes at atemperature substantially equal to a temperature used at the time ofpreheating thus drying a surface of synthetic resin film 160. Byapplying light buffing to the surface at a stage where the surface ofsynthetic resin film 160 is dried, a surface roughness of an outermostsurface of synthetic resin film 160 is finely adjusted and hence, afavorable surface condition can be obtained.

Although nylon buffing which contains abrasive grains and buffing whichuses relatively hard steel may be considered as buffing, it is desirableto apply horsehair buffing to synthetic resin film 160.

Lastly, the synthetic resin film is baked at a temperature ofapproximately 150° C. to 230° C. for approximately 30 minutes to 2hours. With such baking, all diluent in the coating agent is evaporatedso that synthetic resin film 160 can be completely fixedly adhered tothe region of valve plate 117 which is brought into contact with armportion 120 b of suction valve 120.

In general, suction valve seat 141 and discharge valve seat 142 areformed on valve plate 117 so that valve plate 117 has a complicatedshape whereby valve plate 117 is made of a sintered metal material forenhancing productivity and the reduction of cost.

However, usually, a sintered metal material is formed by molding by afilling powdery metal into a mold, by applying a pressure to the metalpowder and by heating a metal powder compact and hence, open pores whichcontinuously communicate with a surface and the inside of the sinteredmetal material are present in the sintered metal material in a scatteredmanner. Accordingly, when refrigeration oil 102 in the refrigerantcompressor pools on a surface of valve plate 117 and impregnates intothe inside of valve plate 117. Impregnated refrigeration oil 102 exudesto the surface of valve plate 117 due to a change in pressure or thelike. Such refrigeration oil 102 is interposed in a gap formed betweenvalve plate 117 and arm portion 120 b of suction valve 120. An adhesionforce is generated due to refrigeration oil 102 interposed in the gap,and this adhesion force sucks arm portion 120 b of suction valve 120 tovalve plate 117.

Accordingly, an amount of an extra force for removing an adhesion forcebecomes necessary to ensure an operation of suction valve 120 and hence,a valve opening operation of suction valve 120 is obstructed wherebydelay in opening is generated. As a result, a pressure loss is generatedthus giving rise to a drawback that efficiency of the refrigerantcompressor is lowered.

To overcome this drawback, by repeating a pressure applying step and aheating step for molding a sintered metal material plural times, densityof the sintered metal material can be increased so that open pores canbe made small. However, such a process increases a manufacturing costand also workability is deteriorated. On the other hand, when a castiron material is used, a number of portions to be worked increases sothat a working cost is pushed up.

In view of the above, in this exemplary embodiment, synthetic resin film160 is formed on at least the region of valve plate 117 which is broughtinto contact with arm portion 120 b of suction valve 120.

With such a configuration, open pores peculiar to a sintered metalmaterial can be sealed by synthetic resin film 160. Further, by applyingsynthetic resin film 160 to valve plate 117, oil repellency of a surfaceof valve plate 117 can be made higher than that of a metal surface.

Due to these actions, it is possible to suppress delay in opening ofsuction valve 120 caused by an adhesive force generated by refrigerationoil 102 interposed in a gap formed between valve plate 117 and armportion 120 b of suction valve 120. Accordingly, a pressure loss in asuction stroke can be reduced and hence, compressor efficiency of therefrigerant compressor can be enhanced.

This advantageous effect is also confirmed by the observation ofbehavior of suction valve 120 by an actual refrigerant compressor. Thedescription is made hereinafter based on result shown in FIG. 8.

FIG. 8 shows the result of the measurement of an impact generated byopening and closing of a valve obtained by an acceleration pickup. Aindicates the result obtained with respect to a refrigerant compressorof the present invention which uses valve plate 117 on which syntheticresin film 160 is formed, and B indicates the result obtained withrespect to a conventional refrigerant compressor which uses valve plate117 on which synthetic resin film 160 is not formed.

As shown in FIG. 6, it is understood that an impact is generated at anearlier rotational angle in the valve plate on which the synthetic resinfilm is formed than that of the conventional valve plate. That is, thevalve plate to which surface treatment is applied exhibits earliertiming at which suction valve 120 opens compared to the conventionalvalve plate and hence, it is proved that delay in opening of suctionvalve 120 can be suppressed.

Next, to compare and study oil repellency of synthetic resin film 160and oil repellency of a metal surface, a spreading speed ofrefrigeration oil 102 on valve plate 117 on which synthetic resin film160 is formed is compared with a spreading speed of refrigeration oil102 on conventional valve plate 117 on which synthetic resin film 160 isnot formed.

Refrigeration oil 102 is dropped on the respective surfaces, and a speedat which refrigeration oil 102 spreads is measured. As a result, it isconfirmed that valve plate 117 on which synthetic resin film 160 isformed exhibits a slower spreading speed than that of the conventionalvalve plate 117 on which synthetic resin film 160 is not formed by 10%or more. When oil repellency is high, the flow of refrigeration oil 102is suppressed so that a spreading speed of refrigeration oil 102 islowered. This observation of behavior proves that valve plate 117 onwhich synthetic resin film 160 is formed exhibits higher oil repellency.

From the above-mentioned result of study, the inventors of the presentinvention have found that delay in opening of suction valve 120 can bedecreased by forming synthetic resin film 160 on the region of valveplate 117 which is brought into contact with arm portion 120 b ofsuction valve 120.

On the other hand, as a conventional technique of decreasing delay inopening, there has been known a technique which lowers the rigidity ofsuction valve 120 by decreasing a thickness of suction valve 120 ornarrowing a width of arm portion 120 b. However, when the rigidity ofsuction valve 120 is lowered, durability of suction valve 120 againstrepeated operations is lowered so that suction valve 120 is liable to bebroken. That is, a lifetime of the refrigerant compressor is lowered.

When the rigidity of suction valve 120 is lowered, a timing at whichsuction valve 120 opens becomes earlier. However, a time necessary forclosing suction valve 120 becomes longer to the contrary. That is, delayoccurs in closing suction valve 120. When delay in closing occurs, aleakage occurs in a compression stroke so that refrigerating ability islowered.

However, according to the present invention, delay in opening can bedecreased without lowering rigidity of suction valve 120 and hence, itis possible to provide a refrigerant compressor which can enhancecompressor efficiency without lowering a lifetime of suction valve 120.

Next, the description is made with respect to a phenomenon that astriking sound occurs between suction valve 120 and valve plate 117 whensuction valve 120 is closed, and noises are generated due to leakage ofthe striking sound to the outside of sealed container 101. Particularly,electrically-operated element 106 adopts inverter driving to satisfy ademand for high efficiency so that electrically-operated element 106 isoperated at a low speed whereby noises which electrically-operatedelement 106 generates are decreased. As a result, a striking soundgenerated between valve plate 117 and suction valve 120 becomesconspicuous thus making a noise problem more serious. Further, this typeof refrigerant compressor is mounted on the household-use refrigeratorand is installed indoors in most cases and hence, the reduction ofnoises is indispensable.

According to this exemplary embodiment, a striking force generatedbetween valve plate 117 and suction valve 120 at the time of closingsuction valve 120 can be reduced due to an elastic effect of syntheticresin film 160 applied to valve plate 117 and hence, the striking soundcan be reduced so that it is possible to provide a refrigerantcompressor which can realize low noises.

Further, due to the reduction of a striking force generated betweenvalve plate 117 and suction valve 120 at the time of closing suctionvalve 120, breaking such as cracks or chippings of suction valve 120 canbe suppressed and hence, it is possible to provide a highly reliablerefrigerant compressor.

Synthetic resin film 160 uses fluororubber as a binder, and afluororesin as solid lubricant 162. Synthetic resin film 160 which usesfluorine exhibits high resiliency compared to other synthetic resinfilms 160, and exhibits high oil repellency property. On the other hand,the utilization of synthetic resin film 160 which uses fluorine toequipment which uses refrigerant oil has been limited due to high oilrepellency of synthetic resin film 160.

According to the present invention, the inventors of the presentinvention have realized the utilization of synthetic resin film 160 byspecifying portions which are not required to surely possess lubricationproperty by refrigerant oil and sealing property. With such aconfiguration, resiliency of synthetic resin film 160 can be furtherenhanced and hence, a striking sound can be further reduced so that itis possible to provide a refrigerant compressor which can realize lownoises.

Further, oil repellency can be also enhanced and hence, delay in openingcan be effectively suppressed whereby it is possible to provide arefrigerant compressor which can enhance compressor efficiency.

Since synthetic resin film 160 contains solid lubricant 162, a shearingforce generated when valve plate 117 and suction valve 120 are closed isreduced due to a lubrication effect of solid lubricant 162. Accordingly,peeling off of synthetic resin film 160 applied to valve plate 117 froma surface of a base material of valve plate 117 can be suppressed andhence, it is possible to provide a refrigerant compressor which exhibitshigh durability for a long period.

In this exemplary embodiment, with respect to the structure of syntheticresin film 160, as binder 161, a synthetic resin made of fluororubber isused. However, with the use of a polyamide-imide resin, an epoxy resin,or a phenol resin which is a thermosetting resin and possesses excellentoil resistance, heat resistance, refrigerant resistance, and organicsolvent resistance, it is possible to acquire substantially the sameadvantageous effects as fluororubber.

In this exemplary embodiment, as solid lubricant 162 scattered insynthetic resin film 160, a fluororesin is used. However, even with theuse of molybdenum disulfide (MoS2), polytetrafluoroethylene resin(PTFE), and graphite (C) in a single form or in mixture, it is possibleto acquire substantially the same advantageous effects as a fluororesin.

Further, when molybdenum disulfide or graphite is used as solidlubricant 162, by using antimony trioxide (Sb2O3) together with thesematerials, antimony trioxide captures air and oxygen which intrude intosynthetic resin film 160 and these materials per se are oxidized firstso that the degradation by oxidation of solid lubricant 162 in syntheticresin film 160 can be suppressed so that synthetic resin film 160 cansufficiently exhibit a wear suppression effect.

In this exemplary embodiment, with the use of an appropriate maskingjig, a pneumatic-cylinder-type dispenser device or the like, it ispossible to apply synthetic resin film 160 by coating only to portionswhich require synthetic resin film 160 and hence, a coating amount canbe reduced whereby productivity of a refrigerant compressor can beenhanced, and the reduction of cost can be achieved.

A total film thickness of synthetic resin film 160 is set to a valuewhich falls within a range of 1 μm to 100 μm. Particularly, when thetotal film thickness of synthetic resin film 160 is set to a value whichfalls within a range of 20 μm to 70 μm, synthetic resin film 160 canacquire the most balanced specification. This is because synthetic resinfilm 160 contains fluororubber as a binder and a fluororesin as thesolid lubricant and hence, even when a film thickness is increased,in-film strength of synthetic resin film 160 and adhesion strength ofsynthetic resin film 160 with an interface of the base material can bemaintained. Accordingly, a striking sound reduction effect can beincreased, and wear and peeling off of synthetic resin film 160 can bealso suppressed. Accordingly, it is possible to provide a refrigerantcompressor which can reduce surface roughness of synthetic resin film160 while ensuring durability thus exhibiting high productivity whileensuring reliability for a long period.

It is needless to say that substantially the same advantageous effectscan be acquired even when synthetic resin film 160 is applied to armportion 120 b of suction valve 120 in the same manner. Further, in thiscase, rigidity of arm portion 120 b of suction valve 120 can beincreased and hence, delay in closing suction valve 120 can besuppressed. Accordingly, the backflow of a sucked refrigerant gas can beprevented, and a volume efficiency can be enhanced and hence, compressorefficiency of the refrigerant compressor can be enhanced.

Second Exemplary Embodiment

FIG. 9 is a cross-sectional view of a main part of a refrigerantcompressor according to a second exemplary embodiment of the presentinvention. FIG. 10 is a plan view of a valve plate on a discharge sideof the refrigerant compressor according to the second exemplaryembodiment of the present invention.

The basic configuration of this exemplary embodiment is equal to theconfiguration in FIG. 1 to FIG. 5 showing the first exemplary embodimentof the present invention and hence, the description of the basicconfiguration of this exemplary embodiment is omitted. Theconstitutional parts identical with the constitutional parts describedin FIG. 1 to FIG. 5 are given the same symbols, and the description ofthese constitutional parts is partially omitted.

In the refrigerant compressor of this exemplary embodiment, syntheticresin film 160 is formed on at least a region of valve plate 117 whichis brought into contact with arm portion 121 b (see FIG. 5) of dischargevalve 121.

Synthetic resin film 160 contains a synthetic resin made of fluororubberas binder 161, and contains a fluororesin as solid lubricant 162 in anapproximately-uniformly scattered manner.

With such a configuration, open pores peculiar to a sintered metalmaterial can be sealed by synthetic resin film 160. Further, by applyingsynthetic resin film 160 to valve plate 117, oil repellency of a surfaceof valve plate 117 can be made higher than that of a metal surface.

Due to these actions, it is possible to suppress delay in opening ofdischarge valve 121 caused by an adhesive force generated byrefrigeration oil 102 interposed in the gap formed between valve plate117 and arm portion 121 b of discharge valve 121. Accordingly, apressure loss in a discharge stroke can be reduced and hence, compressorefficiency of the refrigerant compressor can be enhanced.

This advantageous effect is also confirmed by the observation ofbehavior of discharge valve 121 by an actual refrigerant compressor. Thedescription is made hereinafter based on the result shown in FIG. 8.FIG. 8 shows the result of the measurement of an impact generated byopening and closing of a valve obtained by an acceleration pickup. Aindicates the result obtained with respect to a refrigerant compressorof the present invention which uses valve plate 117 on which syntheticresin film 160 is formed, and B indicates the result obtained withrespect to a conventional refrigerant compressor which uses valve plate117 on which synthetic resin film 160 is not formed.

As shown in FIG. 8, it is understood that an impact is generated at anearlier rotational angle in the valve plate on which the synthetic resinfilm is formed than that of the conventional valve plate. That is, it isproved that the valve plate to which the surface treatment is appliedexhibits earlier timing at which discharge valve 121 opens compared tothe conventional valve plate, and delay in opening of discharge valve121 can be suppressed.

Next, to compare and study oil repellency of synthetic resin film 160and oil repellency of a metal surface, a spreading speed ofrefrigeration oil 102 on valve plate 117 on which synthetic resin film160 is formed is compared with a spreading speed of refrigeration oil102 on conventional valve plate 117 on which synthetic resin film 160 isnot formed.

Refrigeration oil 102 is dropped on the respective surfaces, and a speedat which refrigeration oil 102 spreads is measured. As a result, it isconfirmed that valve plate 117 on which synthetic resin film 160 isformed exhibits a slower spreading speed than that of the conventionalvalve plate 117 on which synthetic resin film 160 is not formed by 10%or above. When oil repellency is high, the flow of refrigeration oil 102is suppressed so that a spreading speed of refrigeration oil 102 islowered. This observation of behavior proves that valve plate 117 onwhich synthetic resin film 160 is formed exhibits higher oil repellency.

From the above-mentioned study of the result, the inventors of thepresent invention have found that delay in opening of discharge valve121 can be decreased by forming synthetic resin film 160 on the regionof valve plate 117 which is brought into contact with arm portion 121 bof discharge valve 121.

On the other hand, as a conventional technique of decreasing delay inopening, there has been known a technique which lowers the rigidity ofdischarge valve 121 by decreasing a thickness of discharge valve 121 orby narrowing a width of arm portion 121 b. However, when the rigidity ofdischarge valve 121 is lowered, durability of discharge valve 121against repeated operations is lowered so that discharge valve 121 isliable to be broken. That is, a lifetime of the refrigerant compressoris lowered.

When the rigidity of discharge valve 121 is lowered, a timing at whichdischarge valve 121 opens becomes earlier. However, a time necessary forclosing discharge valve 121 becomes longer to the contrary. That is,delay occurs in closing discharge valve 121. When delay in closingoccurs, the backflow of a refrigerant occurs in a suction stroke so thata re-expansion loss is increased.

However, according to the present invention, delay in opening can bedecreased without lowering rigidity of discharge valve 121 and hence, itis possible to provide a refrigerant compressor which can enhancecompressor efficiency without lowering a lifetime of discharge valve121.

Next, the description is made with respect to a phenomenon that astriking sound occurs between discharge valve 121 and valve plate 117when discharge valve 121 is closed, and noises are generated due toleakage of the striking sound to the outside of sealed container 101.Particularly, electrically-operated element 106 adopts inverter drivingto satisfy a demand for high efficiency so that electrically-operatedelement 106 is operated at a low speed whereby noises whichelectrically-operated element 106 generate are decreased. As a result, astriking sound generated between valve plate 117 and discharge valve 121becomes conspicuous thus making a noise problem more serious. Further,this type of refrigerant compressor is mounted on the household-userefrigerator and is installed indoors in most cases and hence, thereduction of noises is indispensable.

According to this exemplary embodiment, a striking force generatedbetween valve plate 117 and discharge valve 121 at the time of closingdischarge valve 121 can be reduced due to an elastic effect of syntheticresin film 160 applied to valve plate 117 and hence, the striking soundcan be reduced so that it is possible to provide a refrigerantcompressor which can realize low noises.

It is needless to say that substantially the same advantageous effectscan be acquired even when synthetic resin film 160 is applied to armportion 121 b of discharge valve 121 in the same manner. Further, inthis case, rigidity of arm portion 121 b of discharge valve 121 can beincreased and hence, delay in closing discharge valve 121 can besuppressed. Accordingly, the backflow of a discharged refrigerant gascan be prevented, and a re-expansion loss can be decreased and hence,compressor efficiency of the refrigerant compressor can be enhanced.

Third Exemplary Embodiment

FIG. 11 is a schematic view showing a configuration of a refrigerationappliance according to a third exemplary embodiment of the presentinvention. In this exemplary embodiment, the refrigeration appliance hasa configuration that the refrigerant compressor described in the firstexemplary embodiment or the second exemplary embodiment of the presentinvention is mounted on a refrigerant circuit, and only the basicconfiguration of the refrigeration appliance is schematically described.

In FIG. 11, the refrigeration appliance includes: body 201 formed of aheat-insulating box body having one surface thereof opened and a doorbody which opens and closes the opening; partition wall 207 whichpartitions the inside of body 201 into article storage space 203 andmachine chamber 205; and refrigerant circuit 209 which cools the insideof storage space 203.

Refrigerant circuit 209 is formed by annularly connecting therefrigerant compressor described in the first exemplary embodiment orthe second exemplary embodiment as compressor 211, radiator 213,pressure reduction device 215, and heat absorber 217 by a pipe.

Heat absorber 217 is disposed in the inside of storage space 203equipped with a blower (not shown). Cooling heat of heat absorber 217 isstirred by the blower so that cooling heat circulates in storage space203 as indicated by an arrow. With such an operation, storage space 203is cooled.

On the refrigeration appliance described above, the refrigerantcompressor according to the first exemplary embodiment or the secondexemplary embodiment of the present invention is mounted as compressor211. Compressor 211 is configured such that synthetic resin film 160 isformed on the region of valve plate 117 which is brought into contactwith arm portion 120 b of suction valve 120 or on the region of valveplate 117 which is brought into contact with arm portion 121 b ofdischarge valve 121. With such a configuration, delay in opening ofsuction valve 120 or delay in opening of discharge valve 121 caused byan adhesive force generated by refrigeration oil 102 can be suppressedthus reducing a pressure loss in a suction stroke and a discharge strokeand hence, compressor efficiency is enhanced and, at the same time, astriking sound generated at the time of closing suction valve 120 anddischarge valve 121 can be reduced due to an elastic effect of syntheticresin film 160. Accordingly, the reduction of noises can be realized andhence, power consumption of the refrigeration appliance can be reducedthus realizing the energy saving and, at the same time, the reduction ofnoises.

Fourth Exemplary Embodiment

FIG. 12 is a cross-sectional view of a refrigerant compressor accordingto a fourth exemplary embodiment of the present invention. FIG. 2 is anexploded perspective view of a valve plate of the refrigerant compressorand parts around the valve plate according to the fourth exemplaryembodiment of the present invention. FIG. 12 is a cross-sectional viewof a main part of the valve plate of the refrigerant compressoraccording to the fourth exemplary embodiment of the present invention.FIG. 13 is a plan view of the valve plate of the refrigerant compressoraccording to the fourth exemplary embodiment of the present invention.FIG. 14 is a cross-sectional view showing a surface treatment film ofthe refrigerant compressor according to the fourth exemplary embodimentof the present invention.

As shown in FIG. 12 to FIG. 15, in the refrigerant compressor accordingto this exemplary embodiment, for example, mineral oil having lowviscosity is accumulated on a bottom portion of sealed container 301 asrefrigeration oil 302. For example, R600a or the like which is ahydrocarbon refrigerant having a low global warming coefficient isfilled in sealed container 301 as working fluid 303.

Sealed container 301 is formed by drawing a steel plate. Sealedcontainer 301 includes: suction pipe 350 having one end thereofcommunicating with the inside of sealed container 301 and the other endthereof connected to a low pressure side of a refrigeration cycle (notshown); and discharge pipe 357 which has one end thereof penetratingsealed container 301 and communicating with a discharge muffler (notshown) and the other end thereof connected to a high pressure side ofthe refrigeration cycle (not shown).

In the inside of sealed container 301, compressor body 304 which isprovided with compressive element 309 and electrically-operated element306 is housed in a resiliently supported manner with respect to sealedcontainer 301 by suspension spring 305.

Compressive element 309 is formed of crankshaft 312, block 315, piston316, connecting portion 322, and the like. Crankshaft 312 includeseccentric shaft 310 and main shaft 311. Crankshaft 312 also includes oilsupply mechanism 351 formed of a spiral groove or the like formed on asurface of main shaft 311.

Electrically-operated element 306 is formed of: stator 307 which isthreadedly fixed to a lower side of block 315 by bolts (not shown), androtor 308 which is disposed coaxially inside stator 307 and is fixed tomain shaft 311 by shrinkage fitting. Electrically-operated element 306is driven by an inverter drive circuit at a plurality of operationfrequencies including an operation frequency (for example, 25 Hz=1500r/min) below a commercial power frequency.

In block 315, cylinder 314 which forms compression chamber 313 thereinand bearing portion 323 which rotatably and pivotally supports mainshaft 311 are integrally formed with each other.

On an end surface of cylinder 314 are mounted valve plate 317 which hassuction hole 318 and discharge hole 319 which allow the inside and theoutside of compression chamber 313 to communicate with each other; andsuction valve 320 which opens and closes suction hole 318. Further,cylinder head 352 which seals valve plate 317 is also pressed and fixedto the end surface of cylinder 314 by head bolts 353 so as to seal theend surface of cylinder 314. Suction muffler 354 is held and fixedbetween valve plate 317 and cylinder head 352.

Suction valve 320 is made of a spring steel material and a stainlesssteel material. Suction valve 320 is formed of: fixed portion 320 awhich is fixed to valve plate 317; opening and closing portion 320 bwhich opens and closes suction hole 318 formed in valve plate 317; andarm portion 320 c which connects fixed portion 320 a and opening andclosing portion 320 b to each other.

Valve plate 317 is formed by molding using a sintered metal material. Ona surface of valve plate 317 disposed on a cylinder head 352 side,discharge valve 321 which opens and closes discharge hole 319 isdisposed. Valve plate 317 further includes a discharge valve unit whichis formed of spring lead 330 which resiliently supports discharge valve321, and valve stop 331 which fixes discharge valve 321 and spring lead330 to each other. Head space 356 is formed by valve plate 317 andcylinder head 352.

The operation and function of a reciprocation compressor having theabove-mentioned configuration are described hereinafter.

In the refrigerant compressor, when a magnetic field is generated bysupplying an electric current to stator 307 so that rotor 308 fixed tomain shaft 311 is rotated, crankshaft 312 is rotated, and piston 316reciprocates in cylinder 314 by way of connecting portion 322 mounted oneccentric shaft 310 in a rotatable manner. Along with the reciprocatingmovement of piston 316, working fluid 303 is sucked into compressionchamber 313 through suction muffler 354, and after being compressed,working fluid 303 is discharged to a refrigeration cycle (not shown)through discharge hole 319 and head space 356.

Next, a suction stroke, a compression stroke, and a discharge stroke ofcompressor body 304 are described.

In the suction stroke, when piston 316 is operated in a direction that avolume of compression chamber 313 is increased, working fluid 303 in theinside of compression chamber 313 is expanded. When a pressure incompression chamber 313 becomes lower than a pressure in suction muffler354, due to the difference between the pressure in compression chamber313 and the pressure in suction muffler 354, suction valve 320 isstarted to open. Then, working fluid 303 of a low temperature which hasreturned from the refrigeration cycle is temporarily released intosealed container 301 from suction pipe 350 and, thereafter, workingfluid 303 flows into compression chamber 313 through suction muffler354.

Thereafter, in the compression stroke, when piston 316 turns thedirection of movement to the direction that the capacity of compressionchamber 313 is decreased from the bottom dead center, the pressure incompression chamber 313 is elevated. Due to the difference between thepressure in compression chamber 313 and the pressure in suction muffler354, suction valve 320 is closed. Then, compression chamber 313 isclosed, and piston 316 is operated in the direction that the volume ofcompression chamber 313 is decreased and hence, working fluid 303 iscompressed, and the pressure in compression chamber 313 is elevated to apredetermined pressure.

Then, in the discharge stroke, when the pressure of working fluid 303 incompression chamber 313 is elevated and becomes higher than a pressurein head space 356 formed by valve plate 317 and cylinder head 352. Whena force generated by the pressure difference exceeds a force forresiliently deforming discharge valve 321, discharge hole 319 is opened.Then, working fluid 303 in compression chamber 313 passes throughdischarge hole 319 and flows out into head space 356. Working fluid 303passes through a discharge muffler (not shown) from head space 356, andis discharged to a high-pressure side of the refrigeration cycle (notshown) through discharge pipe 357.

When the pressure difference between head space 356 and compressionchamber 313 is decreased, and a force which is generated by the pressuredifference and is applied to discharge valve 321 becomes smaller than arestoring force of spring lead 330 and discharge valve 321, dischargevalve 321 is closed so that compression chamber 313 is closed. As aresult, piston 316 moves in a direction toward the bottom dead center,and the refrigerant compressor is shifted to the suction stroke again.

In the refrigerant compressor of this exemplary embodiment, as shown inFIG. 14 to FIG. 16, surface treatment film 360 which contains syntheticresin 361 is formed on a region of valve plate 317 which is formed bymolding using a sintered metal material and opposes arm portion 320 c ofsuction valve 320.

Surface treatment film 360 contains synthetic resin 361 made ofpolyamide-imide (PAI) as a binder, and also contains molybdenumdisulfide which is solid lubricant 362 in a substantially uniformlyscattered manner.

Surface treatment film 360 having the above-mentioned structure isformed by a following method.

Firstly, a temperature of valve plate 317 is elevated to a predeterminedtemperature by applying preheating to valve plate 317. The preheating isperformed for evaporating a solvent dissolved in surface treatment film360 which is applied by coating to the region of valve plate 317 whichopposedly faces arm portion 320 c thus applying surface treatment film360 to valve plate 317 uniformly.

Next, a surface treatment agent which contains solid lubricant 362 andwhose composition is adjusted is applied by spraying to the region ofvalve plate 317 which opposes arm portion 320 c of suction valve 320. Inapplying the surface treatment agent, a masking jig having a shapesuitable for preventing adhesion of a coating agent to an undesiredplace is mounted on valve plate 317.

Thereafter, preliminary drying is performed for several minutes at atemperature substantially equal to a temperature used at the time ofpreheating thus drying a surface of surface treatment film 360. Byapplying light buffing to the surface at a stage where the surface ofsurface treatment film 360 is dried, a surface roughness of an outermostsurface of surface treatment film 360 is finely adjusted and hence, afavorable surface condition can be obtained. Although nylon buffingwhich contains abrasive grains and buffing which uses relatively hardsteel may be considered as buffing, it is desirable to apply horsehairbuffing to surface treatment film 360.

Lastly, the surface treatment film is baked at a temperature ofapproximately 180° C. to 230° C. for approximately 30 minutes to 2hours. With such baking, all diluent in the coating agent is evaporatedso that surface treatment film 360 can be completely fixedly adhered tothe region of valve plate 317 which opposes arm portion 320 c of suctionvalve 320.

In general, suction valve seat 341, discharge valve seat 342, and thelike are formed on valve plate 317 so that valve plate 317 has anon-uniform thickness and a complicated shape whereby valve plate 317 isformed by molding using a sintered metal material for enhancingproductivity and the reduction of cost. Further, recessed portion 332 isformed on valve plate 317 on a side opposite to the suction valve seatfor mounting the discharge valve unit having discharge valve 321 onvalve plate 317, and valve plate 317 has a convex shape toward a suctionvalve 320 side (for example, projecting approximately 10 μm to 100 μm)due to a working strain or the like.

Accordingly, when suction valve 320 closes suction hole 318 formed invalve plate 317, arm portion 320 c of suction valve 320 is brought intocontact with valve plate 317 at a position in the vicinity of a peakportion of the convex shape of valve plate 317 and, thereafter, openingand closing portion 320 b closes suction hole 318 and hence, a strikingforce is generated due to a contact of arm portion 320 c with valveplate 317.

Further, there is a possibility that arm portion 320 c of suction valve320 is broken thus bringing about a compression failure. That is, asdescribed previously, to satisfy a recent demand for high efficiency,the refrigerant compressor is in a situation where a wall thickness ofsuction valve 320 made of a spring steel material is reduced, and therefrigerant compressor is operated in a variable-speed rotation modeavailable by adopting inverter driving so that metal fatigue isaccumulated more in suction valve 320. Accordingly, when the refrigerantcompressor having such a configuration is used for a long time, armportion 320 c of suction valve 320 is broken thus bringing aboutcompression failure.

To overcome such a drawback, conventionally, it has been proposed atechnique where a thickness of valve plate 317 is increased so as toincrease rigidity of valve plate 317 thus suppressing deformation ofvalve plate 317 caused by working. However, in such a technique, avolume in discharge hole 319 is increased so that a compressedrefrigerant is re-expanded whereby performance of the refrigerantcompressor is lowered.

Accordingly, in this exemplary embodiment, by applying surface treatmentfilm 360 which contains synthetic resin 361 to the region of valve plate317 which opposes arm portion 320 c of suction valve 320, valve plate317 has a convex shape toward a suction valve 320 side and hence, whensuction valve 320 closes suction hole 318, arm portion 320 c of suctionvalve 320 is brought into contact with valve plate 317 at a position inthe vicinity of the peak portion of the convex shape. Accordingly, evenwhen a striking force is generated, the striking force is attenuated dueto an elastic effect of surface treatment film 360 which containssynthetic resin 361 and is applied to the region of valve plate 317which opposes arm portion 320 c of suction valve 320. Further, thebreaking of suction valve 320 brought about by the striking force can beprevented.

With such a configuration, it is possible to provide a highly reliablerefrigerant compressor and a refrigeration appliance using therefrigerant compressor.

A total thickness of surface treatment film 360 which contains syntheticresin 361 is set to a value which falls within a range of 1 μm to 50 μm.By setting the total film thickness to 1 μm or more, the refrigerantcompressor can acquire a striking force reducing effect due to anelastic effect, and surface treatment film 360 can be uniformly formed.Further, by setting the total film thickness to 50 μm or less, therefrigerant compressor can ensure both in-film strength of surfacetreatment film 360 and adhesion strength of surface treatment film 360with an interface of a base material of valve plate 317, and surfacesize tolerance and surface roughening of surface treatment film 360 canbe suppressed while ensuring durability. Accordingly, it is possible toprovide a refrigerant compressor which exhibits excellent productivityin addition to ensuring reliability for a long period by suppressingwear and peeling-off of surface treatment film 360. It is also possibleto provide the refrigeration appliance using the refrigerant compressor.

In this exemplary embodiment, synthetic resin 361 made ofpolyamide-imide is used as a binder of surface treatment film 360.However, also with the use of an epoxy resin or a phenol resin which isa thermosetting resin and possesses excellent oil resistance, heatresistance, refrigerant resistance, and organic solvent resistance, itis possible to acquire substantially the same advantageous effects aspolyamide-imide.

In surface treatment film 360 in this exemplary embodiment, as solidlubricant 362 scattered in synthetic resin film 360, molybdenumdisulfide (MoS2) is used. However, also with the use ofpolytetrafluoroethylene (PTFE) and graphite (C) in a single form or inmixture, it is possible to acquire substantially the same advantageouseffects as molybdenum disulfide (MoS2).

Further, when molybdenum disulfide or graphite is used as solidlubricant 362, by using antimony trioxide (Sb2O3) together with thesematerials, antimony trioxide captures air and oxygen which intrude intosurface treatment film 360 and these materials per se are oxidized firstso that the degradation by oxidation of solid lubricant 362 in surfacetreatment film 360 can be suppressed so that surface treatment film 360can sufficiently exhibit a wear suppression effect. Accordingly, the useof antimony trioxide is effective.

In this exemplary embodiment, with the use of an appropriate masking jigor a pneumatic-cylinder-type dispenser device or the like (not shown),it is possible to apply a surface treatment agent by coating only toportions which require surface treatment film 360 and hence, a coatingamount can be reduced whereby it is possible to provide a refrigerantcompressor exhibiting high productivity at a low cost.

It is needless to say that substantially the same advantageous effectscan be acquired even when surface treatment film 360 which containssynthetic resin 361 is formed on arm portion 320 c of suction valve 320.

Fifth Exemplary Embodiment

FIG. 17 is a cross-sectional view of a main part of a valve plate of arefrigerant compressor according to a fifth exemplary embodiment of thepresent invention. FIG. 18 is a front view of the valve plate of therefrigerant compressor according to the fifth exemplary embodiment ofthe present invention.

The basic configuration of this exemplary embodiment is equal to theconfiguration shown in FIG. 12 and hence, the description of the basicconfiguration of this exemplary embodiment is omitted. Theconstitutional parts identical with the constitutional parts describedin FIG. 12 are given the same symbols and the description of theseconstitutional parts is partially omitted.

In the refrigerant compressor according to this exemplary embodiment,surface treatment film 360 which contains synthetic resin 361 is formedon a region of valve plate 317 made of a sintered metal material whichopposes opening and closing portion 320 b of suction valve 320, that is,on suction valve seat 341 which is disposed so as to surround suctionhole 318.

As in the case of this exemplary embodiment, by applying surfacetreatment film 360 which contains synthetic resin 361 to suction valveseat 341, a striking force at the time of closing suction valve seat 341and suction valve 320 can be reduced and hence, breaking such as cracksor chippings of suction valve 320 can be suppressed. Accordingly, it ispossible to provide a highly reliable refrigerant compressor and arefrigeration appliance using the same.

A striking force generated between suction valve seat 341 and suctionvalve 320 at the time of closing suction valve 320 can be reduced due toan elastic effect of surface treatment film 360 which contains syntheticresin 361 and is applied to suction valve seat 341 and hence, thestriking sound can be reduced so that it is possible to provide arefrigerant compressor which can realize low noises, and a refrigerationappliance using the same. Particularly, in the refrigerant compressor,electrically-operated element 306 adopts inverter driving to satisfy ademand for high efficiency so that electrically-operated element 306 isoperated at a low speed whereby noises which electrically-operatedelement 306 generates is decreased. As a result, a striking soundgenerated between suction valve seat 341 and suction valve 320 is liableto become conspicuous. Further, this type of refrigerant compressor ismounted on the household-use refrigerator which is installed indoors inmost cases and hence, the striking sound is liable to become conspicuousand hence, the reduction of noises is indispensable. Accordingly, such aconfiguration is effective.

A usual sintered metal material is molded by filling powdery metal intoa mold, by applying a pressure to the metal powder and by heating ametal powder compact and hence, open pores which continuouslycommunicate with a surface and the inside of the sintered metal materialare present in the sintered metal material in a scattered manner.Accordingly, a refrigerant leaks through the open pores and hence,sealing property between suction valve seat 341 and suction valve 320 isdeteriorated whereby compressor efficiency is lowered. Particularly, tocope with energy saving, refrigerating oil 302 of low viscosity has beenadopted and hence, sealing property between suction valve seat 341 andsuction valve 320 has been lowered steadily due to refrigerating oil 302whereby lowering of performance of the refrigerant compressor due to thebackflow of working fluid 303 is conspicuous.

To overcome this drawback, conventionally, by repeating a pressureapplying step and a heating step for molding a sintered metal materialplural times, density of the sintered metal material is increased sothat open pores can be made small. However, such a process increases amanufacturing cost and also workability is deteriorated. On the otherhand, when a cast iron material is used, a number of portions to beworked increases so that a working cost is pushed up.

However, in this exemplary embodiment, surface treatment film 360 whichcontains 361 is applied to suction valve seat 341 and hence, open porespeculiar to a sintered metal material which are scattered in suctionvalve seat 341 can be sealed by surface treatment film 360 whichcontains synthetic resin 361. Accordingly, leakage of a refrigerantbetween suction valve seat 341 and suction valve 320 can be reduced andhence, sealing property can be enhanced whereby the backflow of workingfluid 303 in a compression stroke and a discharge stroke can besuppressed. Accordingly, lowering of refrigerating capacity can besuppressed and hence, it is possible to provide a refrigerant compressorwhich can enhance compressor efficiency at a low cost and arefrigeration appliance using the refrigerant compressor.

Further, solid lubricant 362 is contained in surface treatment film 360which contains synthetic resin 361 and hence, a shearing force generatedwhen suction valve seat 341 and suction valve 320 are closed is reduceddue to a lubrication effect of solid lubricant 362. Accordingly, peelingoff of surface treatment film 360 applied to suction valve seat 341 froma surface of a base material of suction valve seat 341 can besuppressed. Accordingly, it is possible to provide a refrigerantcompressor which can ensure high durability for a long period and arefrigeration appliance using the refrigerant compressor.

Further, due to an effect of solid lubricant 362, coarse crests of thevalve seat surface are removed and the valve seat surface becomes smoothat an early stage and hence, sealing property between suction valve seat341 and suction valve 320 can be enhanced. Accordingly, lowering ofrefrigerating capacity caused by leakage can be suppressed at an earlystage and hence, it is possible to provide a refrigerant compressorwhich can enhance compressor efficiency and a refrigeration applianceusing the refrigerant compressor.

A total film thickness of surface treatment film 360 which containssynthetic resin 361 is set to a value which falls within a range of 1 μmto 50 μm. By setting the total film thickness to 1 μm or more, therefrigerant compressor can acquire a striking force reducing effectbrought about by a sealing property enhancing effect and an elasticeffect, and surface treatment film 360 can be uniformly formed. Further,by setting the total film thickness to 50 μm or less, the refrigerantcompressor can ensure durability by ensuring both in-film strength ofsurface treatment film 360 and adhesion strength of surface treatmentfilm 360 with an interface of a base material of valve plate 317 and, atthe same time, surface size tolerance and surface roughening of surfacetreatment film 360 can be suppressed. Accordingly, it is possible toprovide a refrigerant compressor which exhibits excellent productivityin addition to ensuring reliability for a long period by suppressingwear and peeling-off of surface treatment film 360 and a refrigerationappliance using the refrigerant compressor.

In this exemplary embodiment, synthetic resin 361 made ofpolyamide-imide is used as a binder of surface treatment film 360.However, also with the use of an epoxy resin or a phenol resin which isa thermosetting resin and possesses excellent oil resistance, heatresistance, refrigerant resistance, and organic solvent resistance, itis possible to acquire substantially the same advantageous effects assynthetic resin 361.

In surface treatment film 360 of this exemplary embodiment, as solidlubricant 362 scattered in surface treatment film 360, molybdenumdisulfide (MoS2) is used. However, also with the use ofpolytetrafluoroethylene (PTFE) and graphite (C) in a single form or inmixture, it is possible to acquire substantially the same advantageouseffects as molybdenum disulfide (MoS2). Further, when molybdenumdisulfide or graphite is used as solid lubricant 362, by using antimonytrioxide (Sb2O3) together with these materials, antimony trioxidecaptures air and oxygen which intrudes into surface treatment film 360and these materials per se are oxidized first so that the degradation byoxidation of solid lubricant 362 in surface treatment film 360 can besuppressed so that surface treatment film 360 can sufficiently exhibit awear suppression effect. Accordingly, the use of antimony trioxidetogether with these materials is effective.

In this exemplary embodiment, with the use of an appropriate masking jigor a pneumatic-cylinder-type dispenser device (not shown) or the like,it is possible to apply a surface treatment agent by coating only toportions which require the surface treatment agent and hence, a coatingamount can be reduced whereby it is possible to provide a refrigerantcompressor exhibiting high productivity at a low cost.

It is needless to say that substantially the same advantageous effectscan be acquired even when surface treatment film 360 which containssynthetic resin 361 is applied to opening and closing portion 320 b ofsuction valve 320.

Sixth Exemplary Embodiment

FIG. 19 is a cross-sectional view of a main part of a valve plate of arefrigerant compressor according to a sixth exemplary embodiment of thepresent invention. FIG. 20 is a plan view of the valve plate of therefrigerant compressor according to the sixth exemplary embodiment ofthe present invention.

The basic configuration of this exemplary embodiment is equal to theconfiguration shown in FIG. 12 and hence, the description of the basicconfiguration of this exemplary embodiment is omitted. Theconstitutional parts identical with the constitutional parts describedin FIG. 12 are given the same symbols and the description of theseconstitutional parts is partially omitted.

The refrigerant compressor according to this exemplary embodiment ischaracterized in that, in addition to the configuration of the fourthexemplary embodiment of the present invention or the fifth exemplaryembodiment of the present invention, a surface treatment film 360 whichcontains synthetic resin 361 is formed on a region of a valve plate 317which is formed by molding using a sintered metal material and opposesfixed portion 320 a of a suction valve 320.

With such a configuration, vibrations which are generated by a strikingforce generated between suction valve seat 341 and suction valve 320 atthe time of closing suction valve 320 and propagate through valve plate317 can be attenuated by surface treatment film 360 which containssynthetic resin 361 and is applied to the region of valve plate 317which opposes fixed portion 320 a of suction valve 320. Accordingly, thevibrations and the striking sound can be lowered and hence, it ispossible to provide a refrigerant compressor which realizes thereduction of noises and a refrigeration appliance using the refrigerantcompressor. Particularly, as described previously, the reduction ofnoises is indispensable for a refrigerant compressor and hence, such aconfiguration is effective.

A total film thickness of surface treatment film 360 which containssynthetic resin 361 is set to a value which falls within a range of 1 μmto 50 μm. By setting the total film thickness to 1 μm or more, therefrigerant compressor can acquire an effect of attenuating vibrationsgenerated by a striking force, and surface treatment film 360 can beuniformly formed. Further, by setting the total film thickness to 50 μmor less, the refrigerant compressor can ensure durability by ensuringboth in-film strength of surface treatment film 360 and adhesionstrength of surface treatment film 360 with an interface of a basematerial of valve plate 317 and, at the same time, surface sizetolerance and surface roughening of surface treatment film 360 can besuppressed.

Accordingly, it is possible to provide a refrigerant compressor whichexhibits excellent productivity in addition to ensuring reliability fora long period by suppressing wear and peeling-off of surface treatmentfilm 360, and a refrigeration appliance using the refrigerantcompressor.

In this exemplary embodiment, synthetic resin 361 made ofpolyamide-imide is used as a binder of surface treatment film 360.However, also with the use of an epoxy resin or a phenol resin which isa thermosetting resin and possesses excellent oil resistance, heatresistance, refrigerant resistance, and organic solvent resistance, itis possible to acquire substantially the same advantageous effects assynthetic resin 361.

In surface treatment film 360 of this exemplary embodiment, as solidlubricant 362 scattered in surface treatment film 360, molybdenumdisulfide (MoS2) is used. However, also with the use ofpolytetrafluoroethylene (PTFE) and graphite (C) in a single form or inmixture, it is possible to acquire substantially the same advantageouseffects as molybdenum disulfide (MoS2). Further, when molybdenumdisulfide or graphite is used as solid lubricant 362, by using antimonytrioxide (Sb2O3) together with these materials, antimony trioxidecaptures air and oxygen which intrude into surface treatment film 360and these materials per se are oxidized first so that the degradation byoxidation of solid lubricant 362 in surface treatment film 360 can besuppressed so that surface treatment film 360 can sufficiently exhibit awear suppression effect. Accordingly, the use of antimony trioxidetogether with these materials is effective.

In this exemplary embodiment, with the use of an appropriate maskingjig, a pneumatic-cylinder-type dispenser device (not shown) or the like,it is possible to apply a surface treatment agent by coating only toportions which require surface treatment film 360 and hence, a coatingamount can be reduced whereby it is possible to provide a refrigerantcompressor exhibiting high productivity at a low cost.

It is needless to say that substantially the same advantageous effectscan be acquired even when surface treatment film 360 which containssynthetic resin 361 is formed on fixed portion 320 a of suction valve320.

Seventh Exemplary Embodiment

FIG. 21A is a plan view of a valve plate of a refrigerant compressoraccording to a seventh exemplary embodiment of the present invention.FIG. 21B is a cross-sectional view of the valve plate of the refrigerantcompressor according to the seventh exemplary embodiment of the presentinvention.

The basic configuration of this exemplary embodiment is also equal tothe configuration shown in FIG. 12 and hence, the description of thebasic configuration of this exemplary embodiment is omitted. Theconstitutional parts identical with the constitutional parts describedin FIG. 12 are given the same symbols and the description of theseconstitutional parts is partially omitted.

In the refrigerant compressor according to this exemplary embodiment,recessed portion 332 is formed on a region of valve plate 317 whichopposes arm portion 320 c of suction valve 320 on a side opposite tosuction valve seat 341 of valve plate 317.

A discharge valve device is mounted on recessed portion 332. Thedischarge valve device includes: discharge valve 321 which opens andcloses discharge hole 319 and is disposed on recessed portion 332;spring lead 330 which resiliently supports discharge valve 321; andvalve stop 331 which fixes discharge valve 321 and spring lead 330.

Due to the formation of recessed portion 332, a thickness of valve plate317 becomes partially thin. Accordingly, valve plate 317 is formed intoa convex shape toward suction valve 320 side due to a distortiongenerated at the time of molding and applying finish working to valveplate 317. Particularly, region of valve plate 317 which opposes armportion 320 c of suction valve 320 becomes a convex-shaped apex.

When suction valve 320 closes suction hole 318, arm portion 320 c ofsuction valve 320 is brought into contact with an area near theconvex-shaped apex of valve plate 317 so that a strong striking force isliable to be generated. However, due to an elastic effect of surfacetreatment film 360 which contains synthetic resin 361 which is appliedto a region of valve plate 317 which opposes arm portion 320 c ofsuction valve 320, the striking force is alleviated and hence, it ispossible to provide a refrigerant compressor which enhances reliabilityof suction valve 320 and a refrigeration appliance using refrigerantcompressor.

As has been described heretofore, the refrigerant compressor accordingto the present invention includes, inside a sealed container: a cylinderwhich houses a piston movable in a reciprocating manner; a valve platewhich is disposed on an opening end of the cylinder and has a suctionvalve seat formed so as to surround a suction hole; and a suction valveconfigured to open and close the suction hole, wherein the suction valveincludes an opening and closing portion, and an arm portion configuredto be operated along with opening and closing of the opening and closingportion, and a synthetic resin film is applied to at least a region ofthe valve plate which is brought into contact with the arm portion ofthe suction valve.

With such a configuration, oil repellency of the region of the valveplate with which the arm portion of the suction valve is brought intocontact is enhanced and hence, refrigerant oil is minimally interposedin a gap formed between the valve plate and the arm portion of thesuction valve whereby it is possible to suppress delay in opening of thesuction valve caused by an adhesion force of refrigerant oil.Accordingly, a pressure loss in a suction stroke can be reduced andhence, compressor efficiency of the refrigerant compressor can beenhanced.

A striking force generated at the time of closing the suction valve canbe reduced by an elastic effect acquired by surface treatment and hence,the reduction of noises of the refrigerant compressor can be realized.

The refrigerant compressor according to the present invention includes,inside a sealed container: a cylinder which houses a piston movable in areciprocating manner; a valve plate which is disposed on an opening endof the cylinder and has a discharge valve seat formed so as to surrounda discharge hole; and a discharge valve configured to open and close thedischarge hole. Further, the discharge valve may include an opening andclosing portion, and an arm portion configured to be operated along withopening and closing of the opening and closing portion, and a syntheticresin film may be applied to at least a region of the valve plate whichis brought into contact with the arm portion of the discharge valve.

With such a configuration, oil repellency of the region of the valveplate with which the arm portion of the discharge valve is brought intocontact is enhanced and hence, refrigerant oil is minimally interposedin a gap formed between the valve plate and the arm portion of thedischarge valve. Accordingly, it is possible to suppress delay inopening of the discharge valve caused by an adhesion force ofrefrigerant oil and hence, a pressure loss in a discharge stroke can bereduced whereby compressor efficiency of the refrigerant compressor canbe enhanced.

A striking sound generated at the time of closing the discharge valvecan be reduced by an elastic effect acquired by surface treatment andhence, the reduction of noises of the refrigerant compressor can berealized.

The refrigerant compressor according to the present invention includes,inside a sealed container: a cylinder which houses a piston movable in areciprocating manner; a valve plate which is disposed on an opening endof the cylinder and has a suction valve seat formed so as to surround asuction hole; and a suction valve configured to open and close thesuction hole. The suction valve may include an opening and closingportion, and an arm portion configured to be operated along with openingand closing of the opening and closing portion, and a synthetic resinfilm may be applied to at least a region of the arm portion of thesuction valve which is brought into contact with the valve plate.

With such a configuration, oil repellency of the arm portion of thesuction valve is enhanced and hence, refrigerant oil is minimallyinterposed in a gap formed between the valve plate and the arm portionof the suction valve whereby it is possible to suppress delay in openingof the suction valve caused by an adhesion force of refrigerant oil.Accordingly, a pressure loss in a suction stroke can be reduced, andrigidity of the arm portion of the suction valve can be increased andhence, delay in closing of the suction valve can be suppressed.Accordingly, the backflow of a sucked refrigerant gas can be prevented,and a volume efficiency can be enhanced and hence, compressor efficiencyof the refrigerant compressor can be enhanced.

A striking sound generated at the time of closing the suction valve canbe reduced by an elastic effect acquired by surface treatment and hence,the reduction of noises of the refrigerant compressor can be realized.

The refrigerant compressor according to the present invention includes,inside a sealed container: a cylinder which houses a piston movable in areciprocating manner; a suction valve plate which is disposed on anopening end of the cylinder and has a discharge valve seat formed so asto surround a discharge hole; and a discharge valve configured to openand close the discharge hole. The discharge valve may include an openingand closing portion, and an arm portion configured to be operated alongwith opening and closing of the opening and closing portion, and asynthetic resin film may be applied to at least a region of the armportion of the discharge valve which is brought into contact with thevalve plate.

With such a configuration, oil repellency of the arm portion of thedischarge valve is enhanced and hence, refrigerant oil is minimallyinterposed in a gap formed between the valve plate and the arm portionof the discharge valve whereby it is possible to suppress delay inopening of the discharge valve caused by an adhesion force ofrefrigerant oil. Accordingly, a pressure loss in a suction stroke can bereduced, and rigidity of the arm portion of the discharge valve can beincreased and hence, delay in closing of the discharge valve can besuppressed. Accordingly, the backflow of a discharged refrigerant gascan be prevented, and a re-expansion loss can be reduced and hence,compressor efficiency of the refrigerant compressor can be enhanced.

A striking sound generated at the time of closing the discharge valvecan be reduced by an elastic effect acquired by surface treatment andhence, the reduction of noises of the refrigerant compressor can berealized.

In the refrigerant compressor according to the present invention, thesynthetic resin film may contain fluororubber as a binder, and a solidlubricant may contain a fluororesin.

With such a configuration, resiliency of the synthetic resin film can befurther enhanced and hence, a striking sound can be further reducedwhereby the reduction of noises of the refrigerant compressor can berealized. Further, oil repellency can be also enhanced and hence, delayin opening can be further effectively suppressed so that compressorefficiency of the refrigerant compressor can be enhanced.

In the refrigerant compressor according to the present invention, atotal film thickness of the synthetic resin film may be set to a valuewhich falls within a range of 1 μm to 100 μm.

With such a configuration, a striking sound reduction effect can beincreased, and wear and peeling off of synthetic resin film can be alsosuppressed. Accordingly, it is possible to provide a refrigerantcompressor which can reduce surface roughness of synthetic resin filmwhile ensuring durability thus exhibiting high productivity whileensuring reliability for a long period.

The refrigeration appliance according to the present invention may havea refrigerant circuit which is formed by annularly connecting therefrigerant compressor according to the present invention, a radiator, apressure reduction device, and a heat absorber by a pipe.

With such a configuration, the compressor efficiency can be enhanced.Further, power consumption of the refrigeration appliance can be reducedby mounting the refrigerant compressor which achieves the reduction ofnoises on the refrigeration appliance thus realizing energy saving aswell as the reduction of noises.

The refrigerant compressor according to the present invention mayinclude: a cylinder which houses a piston movable in a reciprocatingmanner; a valve plate which is disposed on an opening end of thecylinder and has a suction valve seat formed so as to surround a suctionhole; and a suction valve configured to open and close the suction hole,and a surface treatment film which contains a synthetic resin may beapplied to a region of the valve plate which opposes an opening andclosing portion of the suction valve or the opening and closing portionof the suction valve.

With such a configuration, a striking force generated between the regionof the valve plate which opposes the opening and closing portion of thesuction valve and the opening and closing portion of the suction valvecan be alleviated by an elastic effect of the surface treatment filmwhich contains a synthetic resin and is disposed in either one of theregion of the valve plate which opposes the opening and closing portionof the suction valve or the opening and closing portion of the suctionvalve. Accordingly, the reliability of the suction valve can be enhancedand a striking sound can be reduced and hence, it is possible to providea refrigerant compressor which realizes high reliability and thereduction of noises.

Further, when the surface treatment film is applied to the region of thevalve plate which opposedly faces the opening and closing portion of thesuction valve, that is, to the suction valve seat, open pores peculiarto a sintered metal material which are scattered in the suction valveseat can be sealed by the surface treatment film which contains asynthetic resin and hence, leakage of a refrigerant between the suctionvalve seat and the suction valve can be reduced whereby sealing propertycan be enhanced. Accordingly, the backflow of a working fluid in acompression stroke and a discharge stroke can be suppressed and hence,it is possible to provide a refrigerant compressor which can reducelowering of refrigerating capacity and can enhance compressorefficiency.

In the refrigerant compressor according to the present invention, asurface treatment film which contains synthetic resin may be disposed ineither one of a region of the valve plate which opposedly faces a fixedportion of the suction valve or the fixed portion of the suction valve.

With such a configuration, vibrations which are generated by a strikingforce generated between the suction valve seat and the suction valve atthe time of closing the suction valve can be attenuated in the course ofpropagation of vibrations through the valve plate by the surfacetreatment film which contains a synthetic resin and is applied to thefixing portion or the fixing portion of the suction valve. Accordingly,the vibrations and the striking sound can be lowered and hence, it ispossible to provide a refrigerant compressor which realizes thereduction of noises.

In the refrigerant compressor according to the present invention, therecessed portion may be formed on a region of the valve plate whichopposedly faces the arm portion of the suction valve on a side oppositeto the suction valve seat.

Due to the formation of the recessed portion, a thickness of the valveplate becomes partially thin. Accordingly, the valve plate is formedinto a convex shape toward a suction valve side due to a distortiongenerated at the time of molding and applying finish working to thevalve plate and hence, a striking force is liable to be generated whenthe suction valve closes the suction hole. However, the striking forceis alleviated by an elastic effect of a surface treatment film whichcontains a synthetic resin and hence, it is possible to provide arefrigerant compressor which enhances reliability of the suction valve.

In the refrigerant compressor according to the present invention, thesurface treatment film which contains a synthetic resin may be a surfacetreatment film which contains a solid lubricant.

With such a configuration, a shearing force generated when the suctionvalve seat and the suction valve or when the discharge valve seat andthe discharge valve are closed is reduced due to a lubrication effect ofthe solid lubricant contained in the surface treatment film.Accordingly, peeling off of the surface treatment film applied to thevalve seat from a surface of a base material of the valve seat can besuppressed and hence, it is possible to provide a refrigerant compressorwhich exhibits high durability for a long period. Further, due to aneffect of the solid lubricant, coarse crests of the valve seat surfaceare removed and the valve seat surface becomes smooth at an early stageand hence, sealing property between the suction valve seat and thesuction valve can be enhanced. Accordingly, lowering of refrigeratingcapacity caused by leakage stage can be suppressed at an early stage andhence, it is possible to provide a refrigerant compressor which canenhance compressor efficiency.

Further, since a synthetic resin contains a solid lubricant, wettabilityof the surface treatment film to refrigerant oil is enhanced and hence,lubrication oil can be held between the valve plate and the valvewhereby a striking force is reduced by an oil film. Accordingly, it ispossible to provide a refrigerant compressor which can further enhancereliability of the suction valve.

INDUSTRIAL APPLICABILITY

As has been described heretofore, the refrigerant compressor accordingto the present invention exhibits high efficiency and exhibits lownoises and hence, the refrigerant compressor according to the presentinvention is applicable to various fields using a refrigeration cyclesuch as an air conditioner, a dehumidifier, a show case, and a vendingmachine, not to mention, a household-use refrigerator.

REFERENCE MARKS IN THE DRAWINGS

-   1, 101, 301: sealed container-   2, 102, 302: refrigeration oil-   3, 103, 303: working fluid-   4, 104, 304: compressor body-   5, 105, 305: suspension spring-   6, 106, 306: electrically-operated element-   7, 107, 307: stator-   8, 108, 308: rotor-   9, 109, 309: compressive element-   10, 110, 310: eccentric shaft-   11, 111, 311: main shaft-   12, 112, 312: crankshaft-   13, 113, 313: compression chamber-   14, 114, 314: cylinder-   16, 116, 316: piston-   17, 117, 317: valve plate-   18, 118, 318: suction hole-   19, 119, 319: discharge hole-   20, 120, 320: suction valve-   21, 121, 321: discharge valve-   23, 123, 323: bearing portion-   52, 152, 352: cylinder head-   56, 156, 356: head space-   115, 315: block-   120 a, 121 a, 320 b: opening and closing portion-   120 b, 121 b, 320 c: arm portion-   122, 322: connecting portion-   141, 341: suction valve seat-   142, 342: discharge valve seat-   150, 350: suction pipe-   151, 351: oil supply mechanism-   157, 357: discharge pipe-   160: synthetic resin film-   161: binder-   162, 362: solid lubricant-   209: refrigerant circuit-   211: compressor-   213: heat radiator-   215: pressure reduction device-   217: hear absorber-   320 a: fixed portion-   332: recessed portion-   360: surface treatment film-   361: synthetic resin

1. A refrigerant compressor comprising, inside a sealed container: acylinder which houses a piston movable in a reciprocating manner; avalve plate which is disposed on an opening end of the cylinder and hasa suction valve seat formed so as to surround a suction hole; and asuction valve configured to open and close the suction hole, wherein thesuction valve includes an opening and closing portion, and an armportion to be operated along with opening and closing of the opening andclosing portion, and the refrigerant compressor further comprises asynthetic resin film in at least a region of the valve plate which isbrought into contact with the arm portion of the suction valve.
 2. Arefrigerant compressor comprising, inside a sealed container: a cylinderwhich houses a piston movable in a reciprocating manner; a valve platewhich is disposed on an opening end of the cylinder and has a dischargevalve seat formed so as to surround a discharge hole; and a dischargevalve configured to open and close the discharge hole, wherein thedischarge valve includes an opening and closing portion, and an armportion to be operated along with opening and closing of the opening andclosing portion, and the refrigerant compressor further comprises asynthetic resin film in at least a region of the valve plate which isbrought into contact with the arm portion of the discharge valve.
 3. Arefrigerant compressor comprising, inside a sealed container: a cylinderwhich houses a piston movable in a reciprocating manner; a valve platewhich is disposed on an opening end of the cylinder and has a suctionvalve seat formed so as to surround a suction hole; and a suction valveconfigured to open and close the suction hole, wherein the suction valveincludes an opening and closing portion, and an arm portion to beoperated along with opening and closing of the opening and closingportion, and the refrigerant compressor further comprises a syntheticresin film in at least a region of the arm portion of the suction valvewhich is brought into contact with the valve plate.
 4. A refrigerantcompressor comprising, inside a sealed container: a cylinder whichhouses a piston movable in a reciprocating manner; a valve plate whichis disposed on an opening end of the cylinder and has a discharge valveseat formed so as to surround a discharge hole; and a discharge valveconfigured to open and close the discharge hole, wherein the dischargevalve includes an opening and closing portion, and an arm portion to beoperated along with opening and closing of the opening and closingportion, and the refrigerant compressor further comprises a syntheticresin film in at least a region of the arm portion of the dischargevalve which is brought into contact with the valve plate.
 5. Arefrigerant compressor comprising, inside a sealed container: a cylinderwhich houses a piston movable in a reciprocating manner; a valve platewhich is disposed on an opening end of the cylinder and has a suctionvalve seat formed so as to surround a suction hole; and a suction valveconfigured to open and close the suction hole, wherein the suction valveincludes an opening and closing portion, and an arm portion to beoperated along with opening and closing of the opening and closingportion, and the refrigerant compressor further comprises a surfacetreatment film containing a synthetic resin, in a region of the valveplate which opposes the opening and closing portion of the suction valveor on the opening and closing portion of the suction valve.
 6. Therefrigerant compressor according to claim 5, wherein the surfacetreatment film containing the synthetic resin is disposed in either oneof a region of the valve plate which opposes a fixed portion of thesuction valve or the fixed portion of the suction valve.
 7. Therefrigerant compressor according to claim 5, wherein a recessed portionis formed on a region of the valve plate which opposes the arm portionof the suction valve on a side opposite to the opening and closingportion.
 8. The refrigerant compressor according to claim 1, wherein thesynthetic resin film is disposed in either one of a region of the valveplate which opposes opening and closing portion of the suction valve orthe opening and closing portion of the suction valve.
 9. The refrigerantcompressor according to claim 1, wherein the synthetic resin filmcontains fluororubber as a binder, and a fluororesin as a solidlubricant.
 10. The refrigerant compressor according to claim 2, whereinthe synthetic resin film contains fluororubber as a binder, and afluororesin as a solid lubricant.
 11. The refrigerant compressoraccording to claim 3, wherein the synthetic resin film containsfluororubber as a binder, and a fluororesin as a solid lubricant. 12.The refrigerant compressor according to claim 4, wherein the syntheticresin film contains fluororubber as a binder, and a fluororesin as asolid lubricant.
 13. The refrigerant compressor according to claim 1,wherein a total film thickness of the synthetic resin film is set to avalue which falls within a range of 1 μm to 100 μm.
 14. A refrigerationappliance comprising a refrigerant circuit which is formed by annularlyconnecting the refrigerant compressor according to claim 1, a radiator,a pressure reduction device, and a heat absorber, by a pipe.
 15. Therefrigerant compressor according to claim 2, wherein a total filmthickness of the synthetic resin film is set to a value which fallswithin a range of 1 μm to 100 μm.
 16. The refrigerant compressoraccording to claim 3, wherein a total film thickness of the syntheticresin film is set to a value which falls within a range of 1 μm to 100μm.
 17. The refrigerant compressor according to claim 4, wherein a totalfilm thickness of the synthetic resin film is set to a value which fallswithin a range of 1 μm to 100 μm.
 18. A refrigeration appliancecomprising a refrigerant circuit which is formed by annularly connectingthe refrigerant compressor according to claim 2, a radiator, a pressurereduction device, and a heat absorber, by a pipe.
 19. A refrigerationappliance comprising a refrigerant circuit which is formed by annularlyconnecting the refrigerant compressor according to claim 3, a radiator,a pressure reduction device, and a heat absorber, by a pipe.
 20. Arefrigeration appliance comprising a refrigerant circuit which is formedby annularly connecting the refrigerant compressor according to claim 4,a radiator, a pressure reduction device, and a heat absorber, by a pipe.